1. Field of the Invention
The present invention generally relates to a method and an apparatus for cooling torque generation assemblies, such as an internal combustion engine and an electric motor and to a vehicle utilizing such an apparatus, and more particularly to a hybrid electric vehicle having an internal combustion engine and an electric motor which are cooled by the use of a variable speed pump which may be selectively activated without the use of the internal combustion engine and the electric motor.
2. Background of the Invention
A vehicle typically utilizes a water pump which is physically coupled to a crankshaft by the use of a belt. More particularly, the engine operatively provides or generates torque which causes the crankshaft to rotate, thereby cooperating with the belt to cause the water pump to operate and to cause coolant to be communicated to the engine from a radiator assembly. While this configuration does desirably provide for the cooling of an engine, it has some drawbacks, especially when used within a hybrid electric vehicle in which torque is selectively generated by the use of an internal combustion engine and/or an electric motor, each of which must be cooled.
For example and without limitation, the previously delineated configuration requires that the engine remain or become operational in order to allow the water or coolant pump to be operational. This requirement, in a hybrid electric vehicle, is particularly undesirable since the internal combustion engine is frequently and purposefully rendered inoperable in order to conserve fuel and to reduce undesirable emissions while the required torque is generated by an electric motor. Hence, in order to cool the electric motor, the internal combustion engine, in a conventional configuration, must be operated even though it is not otherwise operationally necessary. Particularly, such operation reduces the previously delineated and sought-after benefits of such a hybrid configuration.
Moreover, the previously delineated configuration requires that the activation of the pump be dependent upon the activation of the engine and the operational speed of the pump be dependent upon the operational sped of the engine. Hence, should the electric motor require a relatively rapid or xe2x80x9cquickxe2x80x9d cooling, the internal combustion engine must be operated at a relatively high speed which causes the use of a relatively large amount of fuel and which increases the emission of larger amounts of undesirable constituents than are normally emitted at relatively slower speeds. Further, this dependence oftentimes causes the pump to be inefficiently operated (e.g., the pump is operated when cooling is not necessarily required) and causes the cooling assembly, such as the radiator and associated conduits and circuits, (xe2x80x9cthe radiator assemblyxe2x80x9d) to be made larger than necessary in order to accommodate potential and relatively high engine speeds. Moreover, even at a relatively low required engine speed, the pump may be required to be run at high speed as the engine may be xe2x80x9chotxe2x80x9d due to previous engine operation cycles, thereby causing the engine and the vehicle to be inefficiently operated.
Alternatively, to overcome the previously delineated drawbacks, two cooling assemblies are provided, one for the electric motor and one for the internal combustion engine. While this approach does allow a motor to be cooled without the use of an internal combustion engine, it undesirably increases the cost and complexity of the vehicle and still requires each of the cooling assemblies to have an operational speed which is dependent upon the respective torque generation assembly to which they are respectively and operationally coupled.
There is therefore a need for a new and improved method and apparatus for cooling a torque generation assembly and there is therefore a need for a vehicle, such as but not limited to a hybrid electric vehicle, which incorporates such a new and improved apparatus and method.
It is a first non-limiting advantage of the present invention to provide a method and an apparatus for cooling a torque generation assembly in a manner which overcomes some or all of the previously delineated drawbacks of prior cooling configurations.
It is a second non-limiting advantage of the present invention to provide a vehicle incorporating a method and an apparatus for cooling a torque generation assembly in a manner which overcomes some or all of the previously delineated drawbacks of prior cooling configurations.
It is a third non-limiting advantage of the present invention to provide a cooling assembly comprising a radiator assembly containing coolant; and a variable speed pump which is coupled to the radiator assembly and which is operable upon receipt of electrical power to transfer coolant from the radiator assembly.
It is a fourth non-limiting advantage of the present invention to provide an assembly for selectively cooling a motor assembly of a hybrid electric vehicle of the type having an internal combustion engine. Particularly, the assembly comprises a radiator assembly which contains coolant and which is coupled to the internal combustion engine and to the motor assembly; a source of energy; a selectively energizable variable speed pump which is coupled to the radiator assembly; and a controller which is coupled to the variable speed pump and to the source of energy and which selectively energizes the variable speed pump by communicating electric energy to the variable speed pump from the source of energy, effective to cause the variable speed pump to communicate coolant to the motor without the use of the motor and without the use of the internal combustion engine.
It is a fifth non-limiting advantage of the present invention to provide a hybrid vehicle comprising an internal combustion engine; a battery; a motor; a variable speed pump; a reservoir of coolant which is coupled to the internal combustion engine and to the motor; and a controller which selectively activates the variable speed pump by coupling the battery to the variable speed pump, effective to cause the variable speed pump to communicate coolant from the reservoir to the motor without the use of the internal combustion engine and without the use of the motor.
It is a sixth non-limiting advantage of the present invention to provide a method for cooling an engine which may be operable at a certain speed Particularly, the method comprises the steps of providing a reservoir of coolant; providing a variable speed pump assembly which may be operated at a speed which is independent of the speed of the engine; and coupling the variable speed pump to the engine and to the reservoir of coolant, thereby communicating coolant from said reservoir to said engine.
These and other features, and advantages of the present invention will become apparent from a consideration of the following detailed description of the preferred embodiment of the invention and by reference to the following drawings.